Hydraulic press



Dec. 19, 1933. R I 1,939,886

' HYDRAULIC PRESS Filed June l2,-193( 8 Sheets-Sheet 1 gwoe'ntoz W. FERRIS HYDRAULI C PRES S Dec 19, 1933.

Filed Jun 12, 1930 8 Sheets-Sheet 2 dub (A1411 Dec. 19, 1933. i w, fiR s 1,939,886

HYDRAULI C PRES 5 Filed June 12. 1930 8 Sheets-Sheet 3 VVALTER FERRIS.

W. FERRIS HYDRAULIC PRESS Dec. 19, 1933.

FiIedJune 12. 1930 8 Sheets-$heet 5 gnw'ntoc WALT EH FER FHS.

I I I dktoxmq Dec. 19, 1933. w 5 1,939,886

HYDRAULI C PRES 5 Filed June 12. 1930 8 Sheets-Sheet 6 la -Q9 I gwuento'c Dec. 19, 1933. w, F RRls 1,939,886

HYDRAULIC I PRES S Filed June 12. 1930 8Sheets-Sheet '7 gmwnto o \VVALTE Fe FEFR'FHS.

W. FERRI'S HYDRAULIC PRESS Dec. 19, 1933.

Filed June 12. 1930 8 Sheets-Sheet 8 Qwwwfoc Q N WALTER F'EH'HIS.

Patented Dec. 19, 1933 UNITED STATES PATENT OFFICE HYDRAULIC PRESS tion of Wisconsin Application June 12, 1930. Serial No. 460,633

17 Claims. (01. 138 17) This invention relates to a hydraulic press.

The press to which the invention applies in particular has a hydraulically operated ram, an impeller for supplying liquid under pressure to operate the ram, a crankshaft connected to the impeller for operating the same, and a pump for supplying liquid to the hydraulic circuit, such as -the press disclosed in the copending application of Walter Ferris and Glen Macomber', Serial No. 389,368, filed August 30, 1929.

The present invention has as an object to provide a press of this character which is positive and precise in operation and susceptible of close control and adjustment.

Another object is to provide a press with two impellers the phase relation of which may be changed either mechanically or hydraulically to thereby vary the stroke of the press.

Another object is to provide an impeller press with means effective only during operation of the impellers for advancing the ram ahead of the impeller stroke.

Another object is to provide a crank operated hydraulic press in which energy stored in a flywheel is made available to assist the power unit in carrying the peak of the load.

Another object is to provide an impeller press in which the operating range of the ram may be adjusted and the ram automatically stopped at the top of that range.

Another object is to provide an impeller press with a hydraulically actuated clutch and brake which control the drive shaft of the' press and are automatically actuated at a given point in a cycle of operation.

Another object is to provide a hydraulic press in which liquid is discharged from the power circuit when the ram stalls at the end of its working stroke and is automatically returned to the circuit during the following idle stroke of the ram.

Other objects and advantages will appear from the following description of the crank operated hydraulic press which is illustrated in the accompanying drawings and in which the invention is embodied.

The views in the drawings are as follows:

1 is a front view of the press with certain parts shown in section.

Fig. 2 is an elevation of the right side of the press, as indicated by the line 22 of Fig. 1.

3 is a top plan, as indicated by the line 33 of Fig. 2.

Fig. 4 is a sectional plan view of the main driving shaft, taken in the plane of a line 4-4 of Fig. 2 and showing the construction of the clutch and brake.

Fig. 5 is a detail view of one of the impellers, taken on the line 55 of Fig. 1;

Fig. 6 is a section taken on the line 6-601 Fig. 5, showing the construction of the impeller crosshead and the manner in which the impeller plunger is connected thereto.

Fig. 7 is an'elevation of the clutch operating mechanism, taken on the line 7-7 of Fig. 4.

Fig. 8 is an elevation of the operating cam and the mechanism for adjusting the same, taken in the plane of the irregular line 8-8 of Fig. 3.

Fig. 9 is a view of the gearing for adjusting the operating cam, taken on a line 9-9 of Fig. 10.

Fig. 10 is a cross-section on a line 1010 of Fig. 8.

Fig. 11 is an elevation of the brake, taken in the plane of the line 11-11 of Fig. 3.

Fig; 12 is a detail of the hand operating lever.

Fig. 13 is a longitudinal section through the control valve, showing the plunger thereof in the position occupied when the press is in operation.

Fig. 14 is a longitudinal section through the operating valve, showing the plunger thereof in the position occupied when the press is in operation.

Fig. 15 is a view similar to Fig. 14 but showing the valve plunger in another position.

Fig. 16 is a schematic drawing of the hydraulic circuit.

Figs. 1 to 12 The press has two side frames 1 and 2, a guide 3 carried by each side frame, a bed 4 arranged between the lower ends of the side frames, a cross frame or head 5 rigidly connecting the upper ends of the side frames to each other. and a ram 6 arranged between the guides 3 to be guided thereby. The ram 6 is provided with a plunger '1 which has a piston 8 arranged at the upper end thereof and fitted in a cylinder 9 carried by or formed in the cross frame 5. r

The ram 6 is raised and lowered by liquid delivered to the cylinder 9 from two impellers 10 and 11 which are substantially identical as to structure and function and are carried by the side frames v1 and 2, respectively.

The impellers 10 and 11 are provided, respectively, with upper cylinders 12 and 13, which are connected by a pipe 14 to the upper part of the cylinder 9, and with lower cylinders 15 and 16 which are connected by a pipe 17 to the lower part of the cylinder 9.

The impeller 10 has a double-ended plunger 18 which extends into the cylinders 12 and 15 and is adapted to be reciprocated therein by a crosshead 19 which has a bearing block 19 journaled therein and connected to the plunger 18 by a pin 18*, as shown in Fig. 6.

The crosshead 19 is connected by two rods 20 to an upper crosshead 21 which is provided with an anti friction bearing 22 and journaled on a crankpin 23 carried by a gear 24. The crankpin 23 constitutes the crank of a crankshaft 25 which carries the gear 24 and is journaled in bearing brackets 26 and 2'7 arranged upon the cross frame The impeller 11 has a double-ended plunger 28 extending into the cylinders 13 and 16 and adapted to be reciprocated therein by a crosshead 29 which is connected by two rods 30 to an upper crosshead 31 journaled upon the crankpin 32 of a gear 33. The crankpin 32 constitutes the crank of a crankshaft 34 which carries the gear 33 and is journaled in the bearing brackets 26 and 27.

The crankshafts 25 and 34 are driven by a main drive shaft 35 which is journaled in the bearing brackets 26 and 2'7 and has a gear 36 fixed upon one end thereof and permanently in mesh with the gear 33, and a gear 3'7 slidably keyed upon the other end thereof and normally in mesh with the gear 24. The ratio between the gears 24 and 3'7 is the same as the ratio between the gears 33 and 36 so that the crankshafts 25 and 34 are driven in unison and at the same speed.

The gear 37 is fixed for rotation with the shaft 35 by an elongated key 38 and may be moved along the shaft 35 by a screw 39 which has one end attached'to the gear and its other end provided-with two nuts which abut the opposite faces of a flange or collar 40 arranged upon the end of the shaft 35. The key 38 is of sufficient length to allow the gear 3'7 to be moved out of mesh with the gear 24 for changing the phase relation of the two impellers 10 and 11.

The main shaft 35 has a driven gear 41 journaled thereon and meshing with a gear 42 which is fixed upon an idler shaft 43 journaled in bearing brackets 44 and 45 carried by the cross frame 5. The idler shaft 43 carries a gear 46 which meshes with a gear 4'7 arranged upon a flywheel shaft 48 journaled in the bearing brackets 44 and 45. The flywheel shaft 48 is provided with a fiywheel 49 and with a pulley 50 which is connected by a drive 51 to an electric motor 52 carried by the cross frame 5.

The gears 46 and 4'7 are arranged upon the ends of the shafts 43 and 48 outside the bearing bracket 44 and may be readily removed and replaced by gears of a different ratio in order to change the rotative speed of the crankshafts 25 and 34 without altering the rotative speed of the flywheel 49.

Rotation is imparted from the driven gear 41 to the main shaft 35 through a friction clutch 53 which is operated by a hydraulic clutch-operating mechanism 54.

The friction clutch 53 has its hub 55 secured upon the shaft 35 by a key 56 and provided with a fixed pressure plate 5'7 and with movable pressure plates 58 which are slidably keyed thereon. Its friction plates 59 are connected to the gear 41 by pins 60 and are interposed between the pressure plates which are urged away from each other by springs 61. A pressure member 62 is slidably arranged upon the shaft 35, fixed for rotation therewith and urged away from the pressure plate by springs 63.

The springs 61 and 63 keep the clutch disengaged until the pressure member 62 is moved along the shaft 35 by a non-rotatable thrust block 64 which is arranged upon the shaft 35 and adapted to impart pressure to the pressure member 62 through an anti-friction thrust bearing 65 arranged between the same.

The clutch 53 is held against movement toward the driven gear 41 by its hub 55 abutting a shoulder 66 formed on the shaft 35 by an enlarged part 6'7 thereof upon which the driven gear 41 is journaled.

The clutch-operating mechanism 54 has a cylinder support 68 arranged upon the shaft 35 and held against rotation by a link 69 which has one of its ends attached thereto and its other end attached to a bracket '70 carried by the cross frame 5.

The cylinder support 68 carries two cylinders '71 which have pistons '72 fitted therein and engaging the thrust block 64 to hold the same against rotation at all times and to force the same against the roller bearing 65, which transmits the force to pressure member 62 and thereby causes the clutch 53 to be engaged whenever liquid under pressure is supplied to the cylinders '71.

The thrust of the cylinder support 68 is taken by an anti-friction thrust bearing '73 interposed between the same and a thrust collar '74 which is arranged upon the shaft 35 and abutted by a thrust washer '75. The thrust collar '74 and the washer '75 are held against axial movement by a hydraulically operated brake '76 which has its wheel 7'7 fixed upon the shaft 35 by a key 78.

The driven gear 41 is held against movement toward the end of the shaft 35 by a bearing collar '79 which is fitted upon a tapered part of the shaft 35 and held thereon by an annular nut 8l.which is threaded upon the shaft 35. The bearing collar '79 is arranged within the inner race of a roller bearing 82 which is carried by the bearing bracket 26 and protected from dust and dirt by an annular cap 83 secured to the bearing bracket 26.

The brake wheel '77 is held against movement by a similar bearing collar 79 which is journaled in the bearing bracket 27 in a similar manner and like parts have been identified by like reference numerals.

The brake 76 has a pair of brake shoes 84 and 85 which partially encircle the brake wheel '77 and are supported in two bearings 86 carried by the cross frame 5. The shoes 84 and 85 are urged away from the periphery of the wheel '7'? by a helical compression spring 87 and are adapted to be drawn toward each other to grip the wheel '77 by a link 88 which has one end pivoted to the top of the shoe 85 and its other end pivoted to the short arm of a bell crank lever 89 which is pivoted to the top of the shoe 84.

The long arm of the bell crank lever 89 is connected at its outer end by a connecting rod 90 to a piston 91 which is arranged in a cylinder 92 and adapted to force the long arm of the lever 89 upward and'set the brake whenever liquid under pressure is supplied to the cylinder 92.

The operation of the press is controlled by a valve 93 which may be operated manually by either a foot pedal 94 or a hand lever 95 and is operated automatically by a cam 96 carried by 1 the crankshaft 25 and rotatable in unison therewith.

The plunger 9'7 of the valve 93 has its lower stem 98 extended through the valve casing and encircled by a spring 99 which is arranged between the head of the stem 98 and the valve casing to urge the plunger 97 downward.

The valve plunger 97 is held against the action of the spring 99 by an operating lever 100 which is pivoted upon a stationary pin 101 and connected at the outer end of its lower arm to the upper stem 102 of the plunger 97. The other arm of the operating lever 100 is provided at its upper end'with a cam rollerlOS which engages a cam face 104 on the cam 96 when the press is idle and prevents the spring 99 from moving the plunger 97 downward.

The hand lever 95 is pivoted upon a stationary pin 105 and has its end in alinement with the stem 98 so that, when its handle is depressed, the plunger 97 is raised to its upper or operative position as shown in Fig. 13.

The plunger 9'7 may be held in operative position by a spring pressed plunger 106 which is arranged upon the side of the press and adapted, when the hand lever 95 is depressed, to enter a detent 107 formed therein and hold the hand lever against the action of spring 99.

Moving the plunger 97 to its upper or operative position causes the press to'start and it will continue to operate as long as the plunger 9'7 remains in that position. Consequently, the press will continue. to operate until the hand lever 95 is returned to its initial position.

The plunger 97 may also be raised by depressing the pedal 94 which is pivoted upon a stationary pin 108 and has a lifting lever 109 pivoted upon the end thereof and normally engaging a lift rod 110 which is connected at its upper end to the operating lever 100 intermediate the pin 101 and the stem 102 of the plunger 97.

Tht lifting lever 109 is urged by a spring 111 toward the lifting-rod 110 and is provided with a cam face 112 which ordinarily is engaged by the roller 113 of a cam lever 114 pivoted upon a stationary pin 115.

When the pedal 94 is depressed, the lift rod 110 will be raised by the lifting lever 109, the operating lever 100 swung upon its pivot 101, the cam roller 103 swung outward beyond the radius of the cam 96, and the plunger 9'? raised to operative position to start the press.

The operating lever 100 is temporarily latched in this position by a latch 116 which is pivoted upon a stationary pin 117 and urged by a spring 118 into engagement with a projection 119 formed on the lever 100.

If the roller 113 is in engagement with the cam face 112 on the lifting lever 109, as shown in Figs. 2 and 16, the cam lever 114 will move the lifting lever 109 out of engagement with the lift rod 110 when it reaches the limit of its upward movement and immediately after the latch- 116 has plunger 9'1 to remain in its operative position and the press to continue to operate as long as the pedal 94 is held down.

After the press has started, the latch 116 is disengaged from the projection 119 by an arm 120 which is carried by the cam 96 to engage the upper end of the latch 116 and swing the same outward against the action of the spring 118 and release the operating lever 100.

The arm 120 is so located that, when the operating lever 100 is released,-the roller 103 will rest upon the rim of the cam 96 and hold the plunger 97 in its operative position until the-cam 96 has rotated sufficiently to allow the roller 103 to move down upon the cam face 104 and thereby enable When the impellers 10'and 11 are out of phase, z

the stroke of the ram 6 is shortened and, when the crankpins 23 and 32 are separated by an angle of so that the plunger 18 arrives at its uppermost position at the same time that the plunger 28 arrives at its lowermost position, the

ram 6 will remain substantially stationary as the liquid is simply passed from one impeller to the other through the pipes 14 and 17.

The stroke of thepress may be adjusted by moving the gear 37 outward along the shaft 35 until it is out of mesh with the gear 24 so that one crankshaft may rotate independently of the other, then running the press to rotate the crankshaft 34 until the crankpin 32 is in the correst position to produce the length of stroke desired, and then moving the gear 3'? back into mesh with the gear 24.

Instead of rotating the crankshaft 32 by operating the press, the crankshaft 25 may be rotated manually to change the phase relation between the impellers. I

Assuming that the press is in operation and that it has been adjusted to advance the plunger 18 ahead of the plunger 28, the ram 6 will descend at substantially its usual rate of speed until the f 1 plunger 18 arrives at the top of its stroke.

Thereafter, and until the two plungers are in alinement, the ram 6 continues to descend at a decreasing rate-of speed but with an increasing capacity for producing pressure due to a decreasing volume of liquid being supplied to the ram cylinder 9' and an increasing volume of liquid being simply passed from one impeller cylinder to the other.

When the plunger 18 passes below the plunger strokes, at which time, the ram 6 is at the top of its stroke.

The cam 96, therefore, should be adjusted stop the press when the crankpins 23 and 32 are in the lower halves of their respective crank circles and the lower ends of the impeller plungers are substantially the same distance from the ends of their respective cylinders.

As one crankshaft remains stationary when the press is adjusted and the other crankshaft is rotated to produce the entire angle required between the crankpins 23 and 32, the cam 96 need be rotated only one-half the amount that the crankshaft is rotated.

The cam 96 is journalcd upon the outer end of the crankshaft 25 in engagement with an adjusting hub 121 which is also journaled upon the 1';

crankshaft and abuts a shoulder 122 formed thereon. The cam 96 and the hub 121 are held against axial movement by the shoulder 122 and by a nut 123 which is threaded upon the end of the crankshaft 25.

The hub 121 has an arcuate slot 124 formed in its flange 125 to receive a (damping bolt 126 which extends through an arm 127 of the cam 96 to hold the cam in adjusted position relatively to the hub 121.

The cam 96' carries a shaft 128 upon which a gear 129 is arranged in mesh with an internal gear 130 formed in the hub 121. A gear 131 is fixed for rotation with the gear 129, as by being formed integral therewith, and meshes with a gear 132 which is fixed upon the crankshaft 125.

The hub 121 is rotated in synchronism with the crankshaft 34 by a chain 133 which encircles a sprocket 134 carried by the hub 121 and a sprocket 135 carried by the crankshaft 34.

When the press is in operation, the clamping I bolt 126 is tightened to clamp the cam 96 to the hub 121 and the same are rotated by both the chain 133 and the gear 132.

When one crankshaft is stationary and the other crankshaft is rotated, the bolt 126 is loosened and the hub 121 is rotated relatively to the crankshaft 25 by the chain 133. As the gear 132 is fixed to the crankshaft 25, the gear 130 rotates the gears 129 and 131 and carries the gear 131 around the gear 132, causing the cam 96 to be rotated upon the crankshaft 25.

The sprockets and gears are of such a ratio that the cam 96 rotates through one-half the number of degrees through which the crankshaft is rotated in adjusting the stroke of the press, thus automatically adjusting the cam 96 to the correct position to cause the press to be stopped at the top of its stroke.

Figs. 13 to 16 The pressure end of the brake cylinder 92 is connected by a pipe 136, the control valve 93, and a pipe 137 to a constant pressure, variable delivery pump 138 which has the characteristic of delivering liquid at a constant predetermined pressure from a minimum volume of substantially zero to the full capacity of the pump as the demand upon the pump varies. Such a pump is disclosed in Patent No. 1,578,233, issued to me on March 23, 1926. The capacity of the pump, however, is small relatively to the capacity of the impellers, 10 and 11.

The pump 138 thus maintains a constant pressure upon the piston 91 to keep the brake 76 applied as long as the plunger 97 of the valve 93 remains in its neutral position, as shown in Fig. 16. The other end of the brake cylinder 92 is connected by a pipe 139 to a return pipe 140 which discharges into the sump of the pump 138.

In order that the pump" 138 may be removed from circuit temporarily and to insure a constant pressure in the brake cylinder 92 when the press is idle, an accumulator 141 is connected by a pipe 142 to the pipe 137.

The gland end of each clutch cylinder 71 is connected by a pipe 143 to the return pipe 140, and the pressure end of each cylinder 71 is connected by a pipe 144 to a pipe 145 which is connected through a pipe 146, the valve 93 and a pipe 147 to the pipe 140. Both ends of the clutch cylinders are thus open to the return pipe 140 when the plunger 97 is in its neutral position and the clutch release springs 61 are able to keep the clutch 53 disengaged.

in adjusted position upon its upper end.

The ram 6 carries an arm 148 for operating a valve 149 which is supported by the side frame 1, and the stem 150 of its plunger 151 extends through the arm 148 and has a collar 152 secured The valve 149 has a control chamber 153 at its lower end in which a piston 154 is arranged and connected by a rod 155 to the valve plunger 151.

The valve plunger 151 is urged downward by liquid supplied to the upper end of the chamber 153 through a pipe 156 from a gear pump 157 which may be incorporated in the pump 138, as shown in Patent No. 1,578,233, or be separate therefrom.

The downward movement of the valve plunger 151 is initially limited by the collar 152 which engages the arm 148 and holds the plunger 151 in the position shown in Fig. 16 when the press is idle.

The gear pump 157 discharges excess liquid through a relief valve 158 which is connected between the pipes 156 and 140 and is adjusted to maintain a predetermined pressure in the pipe 156.

The valve plunger 151 is moved into the position shown in Fig. 14 when the press is in operation and, should a predetermined pressure be created in the pipe 17, it is adapted to be moved downward to the position shown in Fig. 16 by a piston 159 which is arranged in a cylinder 160 and has an actuator 161 attached to the lower end of its stem 162 for engaging the upper end of th plunger stem 150.

The upper end of the cylinder 160 is connected to the pipe 17 by a pipe 163 and the lower end thereof is connected to the gear pump 157 by a pipe 164 and the pipe 156.

The upper end of the piston 159 is provided with a displacement stem 165 which has a greater cross-sectional area than the stem 162 so that 115 the effective areaof the upper end of the piston 159 is smaller than that of the lower end thereof and the piston159 is supported in its upper position by gear pump pressure until the pressure in the pipe 17 rises a predetermined amount.

The gear pump 157 is also employed to fill the hydraulic circuit with liquid and to maintain the v circuit in a flooded condition at all times, the pipe 164 being connected to the pipes 14 and 17, respectively, through resistance valves 166 and 125 167 which protect the gear pump from the high pressures created by the impellers 10 and 11 and are adjusted to pass liquid at a lower pressure than that maintained in the pipe 156 by the relief valve 158.

When the motor 52 and the pump 138 are in operation, the impeller plungers 18 and 28 are in the positions shown in Fig. 16 and, when the pedal 94 is depressed to raise the lift rod 110 and swing the operating lever 100upon its pivot, the cam roller 103 is swung outward, the latch 116 is urged by its spring 118 into engagement with the projection 119 to hold the lever 100 in that position, and the valve plunger 97 is moved upward into its operative position, as shown in Fig. 13.

The pressure end of the brake cylinder 92 is now open to the return pipe 140 through the pipe 136, the valve 93 and a pipe 168, thus enabling the brake release spring 87 to release the brake 76. 5

The pressure ends of the clutch cylinders 71 are now open to pump pressure through the pipes 144, 145 and 146, the valve 93 and the pipe 137. Thus, raising the valve plunger 97 to its upper position causes the clutch 53 to be engaged and 150 the brake 76 to be released simultaneously and the press started.

The impeller plungers 18 and 28 then move upward and expel liquid from the cylinders 12 .and 13 and force it through the pipe 14 to the upper end of the ram cylinder 9 and thereby cause the rain 6 to move downward.

Also, the lower end of the plungers 18 and 23 move upward and draw liquid from the lower end of the ram cylinder 9 through the pipe 17 and into the cylinders 15 and 16 respectively.

The displacement of the upper end of the plungers 18 and 28 is equal to the a iount of liquid required in the upper end of the cylinder 9 to move the ram 6 downward a predetermined distance, and the displacement of the lower end of the plungers 18 and 28 is equal to the amount. of

' liquid required in the lower part of the cylinder 9 to move the ram upward the same distance irrespective of the adjustment of the press as to the length of its stroke.

The lower end of the pipe 145 is connected to the lower part of the control chamber 153 so that, when the plunger 97 is in its upper position, liquid from the pump 138 may flow through the pipe 137, the valve 93, the pipes 146 and 145 to the control chamber 153. overcome the gear pump pressure upon the piston 154 and raise i t and the plunger 151 to the position shown in Fig. 14.

Liquid from the pump 138 may now flow through the pipe 137, a check valve 169 and a pipe '170 to the valve 149 and then through a pipe 171 to the pipe 14 and advance the piston 8 and the ram 6 ahead of the impellers l0 and 11; the check valve 169 being provided to protect the pump 138 from high pressures which may be created in the valve 149.

As the ram piston 8 is being advanced ahead of the impeller stroke, a larger quantity of liquid is being expelled from the lower part of the ram cylinder 9 than is being drawn into the impeller cylinders 15 and 16 by the plungers 18 and 28, and the excess liquid is d scharged through a low pressure relief valve 172, a needle valve 173 and a pipe 174 to the valve 149 and then through a pipe 175 to the return pipe 140; the pipe 175 being connected to the valve 149 at each end of its valve chamber.

The resistance of the relief valve 172 is sufficient to prevent the passage of liquid when the press is idle, and, consequently, it prevents the downward movement of the ram 6 until the same is forced downward by the impellers 10 and 11.

The adjustment of the needle valve 173 determines the rate at which liquid is delivered to the cylinder 9 by the pump 138 and thus determines the rate at which the ram 6 will move in advance of the impeller stroke.

After the ram 6 starts to move downward, the tripping arm 120 engages the latch 116 and disengages the same from the projection 119, and the roller 103 comes to rest upon the rim of the cam 96 which supports the same and prevents the spring 99 from returning the valve plunger 97 to its initial position until the ram 6 has completed its stroke.

The ram 6 continues to move downward until it reaches the end of its down stroke or until it meets a resistance, and then the pressure in the pipe 14 rises in accordance with the amount of resistance met by the ram 6.

When the ram 6 meets the resistance of the object being operated upon, the pressure in the cylinders 9, 12 and 13 and in the pipe 14 rises and a greater amount of power is required to move' the impeller plungers 18 and 28 upward to force liquid into the upper end of the cylinder 9 to cause the ram piston 8 to continue its downward movement against the increased resistance.

The motor 5? is assisted in overcoming this resistance by the energy stored in the flywheel 49, consequently, a much smaller motor may be employed than would be required if the flywheel energy was not available.

The maximum force exerted by the ram 6 may be positively and accurately regulated by adjusting a high pressure relief valve 176 which has itsinlet connected into the pipe 14 to allow the escape of liquid after the force exerted by the ram hasreachcd the predetermined maximum.

The press and the work to be operated upon are adjusted to stop the ram 6 just before it reaches the limit 01' its down stroke and while the impellers 10 and 11 are still tending to force liquid into the upper end of the cylinder 9.

As the ram 6 is now positively held against further downward movement, the pressure in the pipe 14 rises until the relief valve 176 opens and allows the escape of liquid from the pipe 14.

The maximum force exerted by the ram 6 may thus be accurately regulated by adjusting the valve 176. i

The press is preferably so adjusted that'only a small quantity of liquid escapes through the valve 176, and this quantity of liquid passes from the valve 176 into a chamber 177 in an accumulator 178 which is-connecled to the outlet of the valve 176 and s also connected to the pipe 14 through a check valve 179.

The accumulator 178 has a plunger. 180 which v separates the accumulator chamber 177 from a spring chamber 181 and controls a port 182 with which the return pipe 140 communicates.

The plunger 180 has a valve 183 arranged upon the end of its stem 184 and controlling a passageway 185 through which the stem 184 extends and which communicates with a branch 186 01 the return pipe 140.

The spring chamber 181 contains a helical spring 187 which encircles the stem 184 and 12 normally holds the valve 183 against its seat to close communication, between the passage; way 185 and a chamber 188 which is in open communication with the pipe 17.

The liquid expelled through the relief valve 176 into the chamber 177 tends to force the plunger 180 out of the chamber'l77 against the action of the spring 187, and the valve 183 is moved out of engagement withits seat.

If -the quantity of liquid expelled through the valve 176 is greater than the capacity of the chamber 177, theplunger 180 is moved far enough to uncover the port 182 and allow the liquid in excess of the capacity of the chamber 177 to escape into the return pipe 140, and then the spring 187 urges. the plunger 180 over the port 182 to keep the chamber 177 full of liquid.

Liquid flows from the lower part of the cylinder 9 to the cylinders 15 and 16 as long as the ram piston 8 moves downward but, when the piston 8 stops, no more liquid will be discharged from the cylinder .9 and the upward movement of the impeller plungers 18 and 28 will cause liquid to be drawn into the cylinders 15 and 16 from the sump of the pump 138 through the return pipe 140, the branch 186, the passageway 185. the chamber 188 and the pipe 17.

When the impeller plungers start to move downward to raise the ram 6, the pressure in the cylinders 9, 12 and 13 and in the pipe 14' 150 falls to normal and the spring 187 is able to urge the plunger 180 into the chamber 177 to close the valve 183 and to return liquid from the chamber 177 to the pipe 14 through the check valve 179.

When the impeller plunger-s first start to move downward and before the valve 183 closes, liquid expelled from the cylinders 15 and 16 is returned to the pump 138 through the pipe 17, the chamber 188, the passageway 185, the branch 186 and the return pipe 140.

As soon as the valve 183 closes, the liquid expelled from the cylinders 15 and 16 is forced into the lower part of the cylinder 9 to raise the ram 6 and the liquid in the upper part of the cylinder 9 is transferred to the cylinders 12 and 13.

When the press reaches the limit of its upstroke, crankshaft 25 has rotated the cam 96 to its initial position and the cam roller 103 moves from the rim of the cam to the cam face 104, allowing the spring 99 to return the valve plunger 97 to its initial position.

The pressure end of the brake cylinder 92 is now open to the pump 138 through the pipe 136, the valve 93 and the pipe 137, and the pressure end of the clutch cylinders 71 are open to the return pipe 140 through the pipes 144 so that the brake 76 is applied and the clutch 56 is released at the same time and the press stops.

The valve plunger 97 also interrupts communication between the pump 138 and the lower part of the control chamber 153 so that the piston 154 is forced downward by gear pump pressure until the collar 152 abuts the arm 148 and stops the valve plunger 151 in its initial position. When the piston 154 moves downward, liquid is expelled from the lower part of the control chamber 153 through the pipes 145 and 146, the valve 93, and the pipes 147 and 140 to the sump of the pump 138.

All moving parts are now in their initial position and a second cycle of operation may be started by operating either the pedal 94 or the hand lever 95. However,,if the pedal 94 is held down or the lever 95 has been operated to hold the plunger 97 in its upper position, the brake 76 and the clutch 53 are not actuated and the ram 6 continues to reciprocate until the plunger 97 of the control valve 93 is returned to its initial position.

The pump 138, which is 01' a limited capacity relatively to the impellers 10 and 11, is delivering liquid to the upper end of thecylinder 9 during the entire cycle of operation whenever the pressure therein is lower than the capacity of the pump and, when the ram stalls at the bottom of its stroke, the quantity of liquid expelled through the relief valve 176 is equal to the total quantity of liquid delivered by the pump 138 to the upper end of the cylinder 9 during an entire cycle of operation, less any leakage which may occur.

If considerable force is required to raise the piston 8, as when stripping a formed article from a die carried by the ram 6, the pressure in the pipe 17 rises and the impellers 10 and 11 endeavor inder 160 and move the piston 159 and the actuator 161 downward against the-valve stem 150 and thereby move the valve plunger 151 to its initial position.

The passage of liquid through the needle valve 173 and the pipe 174 is thus stopped by the plunger 151 and the pressure in the pipe 17 and in the lower part of the cylinder 9 will continue to rise until suflicient force is exerted upon the piston 8 to move the ram 6 upward.

If the pressure in the pipe 17 should rise so high that there would be danger of damage to the press, liquid may escape from the pipe 17 through a high pressure relief valve 189 which has its inlet connected to the pipe 17 by a pipe 190 and its outlet connected by the pipe 175 to the return pipe 140.

The ram 6 may be raised and lowered while the press is idle by operating the valve 149 manually.

If the plunger 151 is raised to its upper position as shown in Fig. 14, the pump 138 will deliver liquid through the pipe 137, the check valve 169, the pipe 170, the'valve 149 and the pipe 171 to the upper part of the cylinder 9 and cause the ram 6 to move downward. Liquid will be expelled from the lower part of the cylinder 9 through the pipe 17, the low pressure relief valve 172, the needle valve 173, the pipe 174, the valve 149, and the pipes 175 and 140 to the sump of the pump 138.

If the collar 152 is loosened from the valve stem 150 and the plunger 151 is moved to its lower position, as shown in Fig. 15, the pump 138 will deliver liquid through the pipe 137, the check valve 169, the pipe 170, the valve 149, the pipe 174, the needle valve 173, a check valve 191 which is connected in parallel with the relief valve 172, and then through the pipe 17 into the lower part of the cylinder 9 and cause the ram 6 to move upward. Liquid is discharged from the upper end of the cylinder 9 through the pipe 171, the valve 149 and the pipes 175 and 140 to the sump of the pump 138.

Instead of adjusting the stroke of the press either mechanically or manually, as previously described, it may be adjusted hydraulically;

A normally open shutoff valve 192 is connected into the pipe 137 and may be closed to remove the valve 93 from the pump circuit so that, if the motor is running, the clutch 53 will not be engaged and the press started when the valve plunger 97 is raised to its operative position.

A pipe 193 is connected between the pipe 137 and the cylinder 15 and provided with a shutoff valve 194 which is normally closed to prevent the pump 138 from delivering liquid to the cylinders 15 and 16 when the press is in operation.

The pipe 17 is provided with a normally open shutoff valve 195 which may be closed when the valve 194 is opened and thereby prevent the liquid delivered to the cylinder 15 from passing through the pipe 17 to the cylinders 16 and 9.

When the valves 192 and 195 are closed and the valve 194 is opened, the pump 138 will deliver liquid to the cylinder 15 to urge the plunger 18 upward, and the plunger 18 will tend to force liquid from the cylinder 12 into the cylinder 9 to urge the piston 8 downward, but the piston 8 is supported by the liquid in the lower part of the cylinder 9 which cannot escape while the valve plunger 151 is. in its neutral position.

By raising the plunger 151 to its upper position,

the liquid in the lower part of the cylinder 9 can escape, as previously described, and the ram 6 will move slowly downward.

Upward movement of the plunger 18 causes the crankshaft to rotate and, as the cam hub 121 is held against rotation by the chain 133, the cam 96 will be rotated through one-half as many degrees as the crankshaft rotates, as previously described.

Rotation of the cam 96 may cause the cam roller 103 to move from the cam face 104 outward onto the rim of the cam 96 and cause the valve plunger 97 to be raised to its operative position.

However, the valve 93 has been removed from the pump circuit by closing the valve 192 and no liquid will be delivered to the clutch cylinders '71. Consequently, the clutch 53 will remain disengaged.

When the stroke of the press has been adjusted to the desired length, the plunger 151 is lowered to stop the escape of liquid and, consequently, arrest the upward movement of the plunger 18 and the downward movement of the ram 6. The valve 194 is then closed and the valves 192 and 195 are opened.

The press may then be operated and the cam 96 will cause the ram 6 to stop automatically at the top of its stroke.

By driving the main shaft through the changeable gears 46 and 47, it is possible to utilize the full workcapacity of the press over a wide range of operations.

If the press is employed to perform operations which require a high pressure to be maintained during a considerable part of the working stroke, as when making a deep draw, gears 46 and 4'7 may be installed which will reduce the rotative speed of the crankshafts 25 and 34 relatively to the rotative speed of the flywheel and thereby prolong the time during which the motor may restore the flywheel energy consumed in performing the operation. Consequently, a greater amount of energy may be drawn from the flywheel to assist in performing the operation than would otherwise be possible, The amount of work performed per stroke is thus increased but the number of strokes per time unit is decreased.

If the ram is required to exert a high pressure for only a brief period of time, as in blanking thin material, gears 46 and 47 maybe installed which will increase the rotative speed of the crankshafts and, should heavy material be inserted between the dies when the press is so adjusted, no damage to the press orflywheel will result as the relief valve 176 positively limits the maximum force exerted by the ram.

The invention herein set forth is susceptible of various modifications and adaptations without departing from the scope thereof as hereafter claimed.

The invention is hereby claimed as follows:

1. In a crank-operated hydraulic press having a ram and a cylinder, the combination of two impellers for supplying liquid to each end of said cylinder to advance and retract said ram, means for changing the phase relation between said impellers to thereby change the stroke of said ram, and means effective only during operation of said impellers for delivering additional liquid to said cylinder to advance said ram ahead of the stroke of said impellers and responsive to a predetermined pressure in said cylinder to discontinue the del very thereto of said additional liquid.

2. In a crank-operated hydraulic press having a ram and a cylinder, the combination of two impellers for supplying liquid to each end of said cylinder to advance and retract said ram, and means for delivering liquid to one of said impellers to change the phase relation between said impellers and thereby change the stroke of said ram.

3. In a crank-operated hydraulic press hav ing a ram and a cylinder, the combination of an impeller arranged upon each side of said press for supplying liquid to each end of said cylinder to advance and retract said ram, means for changing the phase relation between said impellers to thereby change the stroke of said ram, and means effective only during operation of said impellers for delivering additional liquid to said cylinder to advance said ram ahead of the stroke of said impellers and responsive to a predetermined pressure in said .cylinder to discontinue the delivery thereto of said additional liquid.

ljIn a crank-operated hydraulic press having a ram and a cylinder, the combination of two impellers for supplying liquid to each end of said cylinder to advance and retract said ram, a pump, means effective only during actuation of said impellers for directing liquid from said pump to said cylinder to advance said ram ahead of the impeller stroke and responsive to fluid pressure in said cylinder to discontinue the delivery thereto of liquid from said pump, and means for changing the phase relation between said impellers to thereby change the stroke of said ram.

5. In a hydraulic press, the combination of a ram cylinder, a ram having a piston arranged in said cylinder, an impeller for supplying liquid to each end of said ram cylinder to advance and retract said ram. a crankshaft connected to said impeller for operating the same, a driver for rotating said crankshaft, means including a,

clutch for connecting said driver to said crankshaft to rotate the same, a brake for holding said crankshaft against rotation, hydraulic means for operating said clutch and said brake simultaneously, and automatic means for operating said hydraulic means to cause said ram to stop at the top of its stroke.

6. In a hydraulic press, the combination of a ram cylinder, a ram having a piston arranged in said cylinder, an impeller for supplying liquid to each end of said ram cylinder to advance and retract said ram, a crankshaft connected to said impeller for operating the same, means including a flywheel for rotating said crankshaft, means including a clutch for connecting said driving means to said crankshaft to rotate the same, a brake for holding said crankshaft against rotation, hydraulic means for operating said clutch and said brake simultaneously, and automatic means for operating said hydraulic means to cause said ram to stop at the top of its stroke.

7. In a hydraulic press, the combination of a ram cylinder, a ram having a piston arranged in said cylinder, two impeller cylinders connected to the pressure end of said ram cylinder for supplying liquid thereto to advance said ram, two impeller cylinders connected to the retracting end of said ram cylinder for supplying liquid thereto to retract said ram, two impeller plungers each having one end arranged in a cylinder connected to the pressure end of said ram cylinder and its other end arranged in one of the other impeller cylinders, a crankshaft connected to each of said impeller plungers for reciprocating the same, a driving shaft connected to said crankshafts for rotating the same, a driver for rotating said driving shaft, means'including a clutch for connecting said driver to said driving shaft, a brake for holding said driving shaft against rotation, and means for operating said clutch and said brake at a definite point in the stroke of said press.

8. In a hydraulic press, the combination of a ram cylinder, a ram having a piston arranged in said cylinder, two impeller cylinders connected to the pressure end of said ram cylinder for supplying liquid thereto to advance said ram, two impeller cylinders connected to the retracting end of said ram cylinder for supplying liquid thereto to retract said ram, two impeller plungers each having one end arranged in a cylinder connected to the pressure end of said ram cylinder and its other end arranged in one of the other impeller cylinders, a crankshaft connected to each of said impeller plungers for reciprocating the same, a driving shaft connected to said crankshafts for rotating the same, means including a flywheel for rotating said driving shaft, means including a clutch for connectingsaid driving means to said driving shaft, a brake for holding said driving shaft against rotation, and means for operating said clutch and said brake at a definite point in the stroke of said press.

9. In a hydraulic press, the combination of a ram cylinder, a ram having a piston arranged in said cylinder, two impellers for supplying liquid to each end of said cylinder to advance and retract said ram, a crankshaft connected to each impeller to operate the same and adjustable relatively to each other to change the phase relation between the same and thereby change the stroke of said press, a driving shaft connected to said crankshafts for rotating the same, means including a clutch for rotating said driving shaft, a brake for holding said driving shaft against rotation, hydraulic means for operating said clutch and said brake, valve means for controlling said hydraulic means, manual means for operating said valve means to cause said brake to be released and said clutch to be engaged to start said press, and automatic means for operating.

said valve means to cause said brake to be applied and said clutch to be disengaged to stop said press.

10. In a hydraulic press. the combination of a ram cylinder, a ram having a piston arranged in said cylinder, two impellers for supplying liquid to each end of said cylinder to advance and retract said ram, a crankshaft connected to each impeller to operate the same and adjustable relatively to each other to change the phase relation between the same and thereby change the stroke of said press, a driving shaft connected to said crankshafts for rotating the same, means including a flywheel and a clutch for rotating said driving shaft, a brake for holding said driving shaft against rotation, hydraulic means for operating said clutch and said brake, valve means for controlling said hydraulic means, manual means for operating said valve means to cause said brake to be released and said clutch to be engaged to start said press, and automatic means for operating said valve means to cause said brake to be applied and said clutch to be disengaged to stop said press.

11. In a hydraulic press, the combination of a ram cylinder, a ram having a piston arranged in said cylinder, two impellers for supplying liquid to each end of said cylinder -to advance and retract said ram, a crankshaft connected to each impeller to operate the same and adjustable relatively to each other to change the phase relation between the same and thereby change the stroke of said press, a driving shaft connected to said crankshafts for rotating the same, means including a clutch for rotating said driving shaft, a brake for holding said driving shaft against rotation, hydraulic means for operating said clutch and said brake, valve means for controlling said hydraulic means, manual means for operating said valve means to cause said press to be started, automatic means including a cam for operating said valve means to cause said press to stop, and means for automatically adjusting said cam simultaneously with the adjustment of said crankshafts whereby said automatic means will cause said press to stop at the top of its stroke.

.12. In a crank operated hydraulic press hav ing a ram and a cylinder, the combination of two impellers for supplying liquid to each end of said cylinder to advance and retract'said ram, a pump connected in circuit with said impellers, and means for delivering liquid from saidpump to one of said impellers to change the phase relation between said impellers and thereby change the stroke of said ram.

13. In a hydraulic press having a ram and a cylinder, the combination of an impeller for delivering liquid to each end of said cylinder to advance and retract said ram, a pump, means effective only during actuation of .said impeller for directing liquid from said pump to said cylinder to advance said ram ahead of said impeller,

and an accumulator for storing liquid from said cylinder, the combination of an impeller for delivering liquid to each end ofsaid cylinder to advance and retract said ram, a pump, means effective only during actuation of said impeller for directing liquid from said pump to said cylinder to advance said ram ahead of said impeller, a relief valve for limiting the force exerted by said ram, and an accumulator'connected in circuit with said relief valve for storing liquid from said impeller after said ram has exerted a predetermined force and for returning said stored liquid to said impeller upon said ram being retracted.

15. In a hydraulic press having a ram and a cylinder, the combination of an impeller for delivering liquid to each end of said cylinder to advance and retract said ram, a pump, means effective only during actuation of said impeller for directing liquid from said pump to said cylinder to advance said ram ahead of said impeller, and an accumulator for storing a given quantity of liquid from said impeller and for discharging all liquid in excess of said given quantity delivered by said impeller after said ram has exerted a predetermined force and for returning said stored liquid to said impeller upon said ram being retracted.

16. In a hydraulic press having a ram and a cylinder, the combination of two impellers for delivering liquid to said cylinder to advance and retract said ram, a crankshaft for driving each impeller, means for driving said crankshafts, a control valve for controlling the operation of said press, manual means for operating said valve to start a cycle of operation, means for operating said valve automatically to stop said press at the end of a cycle of operation, means for changing the phase relation between said crankshafts to thereby change the stroke of said ram, and means for automatically adiusting said automatic valve operating means simultaneously with the chang ing 01' the phase relation between said crankshaits start a cycle of operation, including a cam for operating said valve automatically to stop means for rotating one crankshaft independent- 1y of the other crankshaft to change the phase relation therebetween, and means for rotating said cam simultaneously with the rotation of said crankshaft and thereby adjust said automatic valve operating means to stop said press at the end 01' a cycle of operation irrespective of the length of ram stroke.

WALTER FERRIS.

said press at the end of a cycle of operation,

ios 

